Air conditioning for cars



Sept. 24, 1935. F. o. MARSHALL AIR CONDITION-ING FOR CARS Filed NOV. 9, 1952 4 Sheel,s-Sl'1ee1'I l /Zf/zA 96574 ovn/ey.

Sept. 24, 1935. F. o. MARSHALL 2,015,489

AIR CONDITIONING FOR CARS Filed Nov. 9, 1932 4 Sheets-Sheet 2 OPTI@ 5S Sept. 24, 1935. F. o. MARSHALL AIR CONDITIONING FOR CARS Filed Nov. 9, 1952 4 Sheets-Sheet 3 Zaun-,Veg

Sept. 24, 1935. F, o. MARSHALL 2,015,489

AIR CONDITIONING FOR CARS Y Filed Nov. 9, 1952 4 Sheets-Sheet 4 Patented Sept. 24, 1935 PATENT l'OFFICE AIR CONDITIONING FOR CARS Frank 0. Marshall, Chicago,

Ill., assignor to Pullman Car and Manufacturing Corporation,

Chicago, Ill., a corporation of Delaware Application November 9, 1932, Serial No. 641,823

7 Claims.

The principal Vobject of this invention is to supply a passenger car with cool, clean air at a minimum cost and with the least possible changes in the car and its regular equipment.

Generally speaking this is accomplished by- (1) Evaporating water with a copious current of air drawn from and returned to the outside of the car'whereby the latent heat of evaporation amounting to 1080 B. t.u. per pound -is taken up and ejected from the car;

(2) Passing the air supply for the car in heat exchange relation with the evaporation area whereby the air supply is cooled without increasing its moisture content;`that is, its wet and dry bulb temperatures are lowered but its constituent of Water vapor is not increased; and

(3) (Whenconditions make it appropriate), subjecting the cooled air supply to further cooling to reduce its dry bulb temperature as by treating it with a spray of cool or cold Water,

which will also thoroughly clean the air.

Further objects and advantages of the invention will become apparent as the disclosure proceeds and the description is read in connection with the accompanying drawings which are -largely diagrammatic and in the main illustrative.

Fig. 1 is part side elevation and part longitudinal section of a Pullman sleeping car, equipped according to the invention;

Figs. 2 and 3 are vertical sections taken 0n the lines 2-2 and 3-3 respectively of Fig. 1;

Fig. 4 is an enlarged longitudinal sectional view similar to the upper portion of Fig. 1, and

Fig. 5 is a transverse 'sectional view through the upper portion of the car looking downward. But these drawings and the specific description are used for the purpose of disclosure only and are not intended to indicate the scope of the invention, and it is realized that the same may be embodied in various forms and applied to various uses.

General description O. sumed without addition to the drawings, a1-

' though the apparatus here illustrated was designed and first applied to the Pullman sleeping car Gloucester, which diiers from the iloor plan in the Car Builders Cyclopedia in some features not material here.

The conventional sleeping car has a clearstory and includes a main roof or lower deck I0, deck sides II and an upper deck I2 (see Figs. 2 and 3).

'I'here is a vestibule I3 adjacent to each end connected with the passenger seating space I4 by a passage I5 (Fig. 3) alongside a lavatory space I6. The roof zone above the passageway and lavatory is, in the main, unoccupied and, for that reason, is selected as the location of the .principal parts of the air conditioning apparatus.

'I'he passenger space is supplied with 2500 cubic feet of air per minute which enters inlets I'I (Fig. 5) through one deck side II, under the impulse of a fan I8 that forces it through a bank of tubes I9, then through a spray chamber 20 15 counter to a cool water spray from whence it escapes through eliminator plates 2| into` a delivery conduit 22 running lengthwise to the passenger space, and provided with two series of openings 23 by which the air is distributed uniformly and without draft.

Five thousand (5000) cubic feet of air per minute used for evaporation enters the inlets 24, circulates around the tubes I9 and through a water spray, falling on them, escapesbetween the eliminator plates 25 under the impulse of a fan 26,.which forcibly ejects it through outlets 21 through the deck side opposite to that where it entered.

From this it will be seen that the air supply for the passengers is first cooled in the tubes I9 Without adding to its moisture content (whereby its wet and dry bulb temperatures are reduced) and then is further cooled and washed by running counter to a spray of cool or cold water (whereby its dry bulb temperature is further reduced) and then is delivered to and distributed in the passenger space. The quantity of water discharged from the last mentioned spray is preferably limited so that additional cooling is obtained without permitting the air to become saturated with moisture so as to produce undesirable humidity conditions.

As a general rule, the coolingthus obtained will be suiiicient for the comfort of the passengers, but under extreme conditions further cooling may be desired, and can be had by treating the spray water with ice or mechanical refrigeration apparatus, which the knowledge of the art will readily supply.

Specific description The inlets 24 are made through conventional ventilator openings in the side deck II, and are tted with louvres 28 and screen 29. The con- 55 leading to the three outlets 21.

struction of the inlet passages may be varied so widely that a specic description is deemed inappropriate.

Theydeliver into what may be called, for convenience, a treatment chamber or evaporation chamber, which takes, roughly, 'the form of a six-sided box, including a curved top.30 (Fig. 3), upright sides 3I-, 32, upright ends 33, 34,-and a bottom 35 sloped to a drain 36, leading into a tall receiving tank 31, located in the wall between the passageway and the lavatory.

The gently curved exit, or outlet 38, (Fig. 5) through the side wall 32, forms the inlet to the centrifugal fan 26, equipped with aropev drive 39, leading to a two-horse power motor 40. The fan 26 delivers into a discharge passage 4I,

The tubes I9 pass through the ends 33 and 34, and are made airtight therewith, to prevent any leakage of evaporation air or water into the path of the supply air. The tubes are of thin copper, tinned inside and outside, and their ends are upset and brazed to the walls 33 and 34 which, like the other parts of the box-like chamber, are of galvanized iron. The number and arrangement of the tubes I9, shown in Fig. 3, will serve as a" guide, but of course, may be varied quite widely, according to the conditions.

The spray water for evaporation is delivered by a pipe, or header, 42, extending lengthwise above the tubes 33, and equipped with ve pairs of nozzles 43.

A pump 44, mounted beneath the car, supplies i'lfty gallons of water per minute under ten pounds pressure, drawn through piping 45 from the bottom of the tank 31 and delivered through piping 46 to the header 42. The pump used to force the water through the circuit is of any suitable type,-and is driven by three-quarter horse power electric motor.

Water lost by evaporation is replenished from an auxiliary tank 41, also supported beneath the A car and connected with the wash water pressure system that is familiar to all car builders.

A pipe 48 (Fig. 1) of this system is provided with a magnetically operated valve 49 of suitable make which is controlled by a snap switch 50, operated by a iioat 5I in the tank 31. Piping 52 leads from the valve 49 to the upper portion of the tank 31. l

As shown best in Fig. 3, the eliminator plates 25 extend about half-way up from the bottom. 35 of the evaporation chamber and terminate against the lower edge of a baille 53, extending lengthwise to the evaporation chamber between the ends 33 and 34.

Adjacent to the outlet 38 for evaporation air and below it is a surge baflie 54 to deect water in the bottom of the chamber.

The spray chamber 20 is dened by sides 55 and 56 extending between the end 34 of the evaporation chamber and a low wall 51, all of which are connected by a bottom 58 to form a sump or tank for the spray water. Piping 59 connects this tank with the pipe 48 of the pressure system, and the ow is controlled by a float valve 60 located in the tank.

Another pump 6I, driven by a three-quarter horse power electric motor, draws fifteen gallons of water per minute from this tank through piping 62, and delivers it under twenty pounds pressure through piping 63 to a header 64 arranged transverse to the spray chamber and equipped with a plurality of spray heads 65.

A false bottom 66 is arranged to catch any leakage from the evaporation chamber and the spray chamber, and piping 61 is supplied to conduct the water away.

The inlets I1 for air to be conditioned are provided with louvres 6 8, having some dust ex- 5 cluding devices 69, here shown as wire screens, but when the cleaning and cooling spray is omitted they should be actual filters.- The details of the inlet passages are a matter of choice and may, indeed, be inserted through the vesti- 10 bule ceiling 10 instead of the deck side II.

The air flow is induced by the centrifugal blower I8; driven by one horse power electric motor 1I at 1750 revolutions per minute. The delivery spout of the blower is extended by a ,15 funnel shaped housing 12 which is made fast to the end 33 of the evaporation chamber so as to conduct the air into the ends of the tubes I9.

These tubes are made as thin as is practicable and their interior surface is increased by plates 20 or fins 13 extending lengthwise and soldered or brazed to the tubes. For general purposes the tinned copper aforementioned, is more suitable, but where neither alkali nor salt is in the air aluminum may be used to advantage. 25

Eliminator plates 2I are arranged in a 4funnel shaped conduit 14 (Figs. 1 and 4) leading to an opening in a bulk head15, and delivering to the conduit 22. This conduit is formed by inserting a longitudinal plate -16 stayed at the middle by 30 braces 11 and joined at the sides by the perforated angle pieces 18. However, the delivery conduit and such are matters of selection.

Power for operating the motors will ordinarily be drawn from the axle generator system most 33 commonly used on cars but, of course, may be supplied otherwise as conditions may suggest. The location and arrangement of switches, thermostats, and other control devices is a matter of choice. 40

As a general thing it will be convenient to control the two water circuits and the two air circuits separately, for in some instances proper ventilav tion will be had without operating all of the apparatus. For example, on one part of a run it will be suflicient to operate the blower I8; at a later time it will be helpful to start the spray in the chamber 20, and still later to put the evaporating chamber in full operation. On runs between Chicago and Los Angeles a car equipped as here 50 disclosed has been found clean and comfortable all the way. As a general thing the air is delivered at a reduced wet bulb temperature and a materially reduced dry bulb temperature.

The eiiiciency of the system will, of course, be 55 greatly aiected by the insulation provided, but the skill of the car builder will be suilicient to supply all such details without any description.

I claim as my invention:

1. In apparatus for cooling air in a passenger 60 car, a treatment chamber between deck sides, an inlet and an outlet through the deck side connecting the chamber with the outside air, means for sending a copious draft of outside air through the chamber, a heat exchanger comprising thin 65 walled tubes traversing the chamber, and exposing large surface areas tothe draft, means for spraying the tubes with water, and means for sending a current of air through the tubes into the car.

2. In .a passenger car having a passenger space, a lavatory and a passageway at one side of the lavatory, a treatment chamber above the lavatory in communication with the outside air, a tank between the lavatoryvand the passageway and 75 aouaao connectedv with the bottom of the chamber, a heat exchanger in the chamber having passages in line of communication with the outside and the passenger space, means for drawing water i'rom the tank and spraying it on the heat exchanger, means for forcing a copious current of outside air over the heat exchanger, and means for passing air through the heat exchanger and into the passenger space.

3. In a. passenger car having a passenger space, a lavatory and a passageway at one side of the lavatory, a treatment chamber above the lavatory in communication with the outside air, a tank between the lavatory and thev passageway and connected with the bottom of the chamber, a spray tank beneath the car in communication with the rst tank, means for forcing waterfrom the spray tank to the first tank, means for controlling the water level in the rst tank, a heat exchanger in the chamber having passages in line of communication with the outside and the passenger space, means :for drawing water from the tank and spraying it on the heat exchanger, means for forcing a copious current of outside air over the heat exchanger, and means for passing air through the heat exchanger and into the passenger space.

4. In a passenger car, a blower, a tubular heat exchanger and a spray chamber in sexies between the outside and the passenger space, means for discharging a spray over the heat exchanger, means for collecting the excess water from the heat exchanger spray and using it as a spray in the spray chamber, and means for passing a copious current of outside air over the heat exchanger.

5. In a passenger car having a main roof, an

vupper deck and deck sides, an evaporating cham- 5 ber having an inlet through one deck side and an outlet through the other deck side, a heat exchanger in the chamber, means for wetting the heat exchanger, means for passing a copious current of air in at the inlet through the chamber over the wetted heat exchanger and out at the outlet, and means for passing air through the heat exchanger and into the car.

6. The method of conditioning air by the evaporation of water which consists in passing the air to be cooled in heat exchange relation, but not in direct contact with a spray of water through which a copious draft of outside air is passed and using the excess water from said spray for further cooling the conditioned air by direct contact with said air.

7. In apparatus for cooling the air, the combination of a treatment chamber, a metal heat exchanger in said chamber providing a passage for air through the heat exchanger, a spray chamber, means for forcing air through said heat exchanger and spray chamber, means for circulating air in copious quantities over the exterior of the heat exchanger, and a closed circuit for discharging water over said heat exchanger and thence through the spray in the spray chamber.

FRANK O. MARSHALL. 

